View Full Version : Lighting : Outdoor Lighting/Shadows
Joel Hooks 07-08-2003, 06:10 PM I am lighting an outddor scene that is pretty large (.5 miles x .5 miles) and I am having troubles getting the shadows to be crisp across the whole scene. If I use a direct light to simulate the sun, the xshadow maps (its a shadowmap that works through opacity like simulated raytrace) need to be too large and use all my memory.
Is there a method that would use multiple lights to keep the shadows tight, but not overlap and creat weird too bright areas?
Any tips are welcome (raytracing is not an option)...
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edaddy
07-08-2003, 09:00 PM
i would use a standard 3 point lighting set up with only one light casting shadows. actually i usually get nice results w/ my fill lights also casting shadows w/ a very low density...
to keep your shadows crisp over a large area try using a 'target direct' light rather than a spot or omni. And you also might have to play around w/ shadow density/bias/sample range as well.
good luck
Libor
07-09-2003, 02:19 PM
Sorry edaddy but it doesn´t solve lowdowns problem:shame:
I have faced the same problem some time ago, the solution is to light key objects separatedly from terrain by pointing lights with small hotspot on them so their shadows are nice and map size is reasonable sized. Then you ve got ugly bright spots where interfere "big light" with small one but with nice shadows. To avoid brighter spots make clone of the "small light" and set clones multiplier negative so it cast the same amount of negative light as the original light (also turn off casting shadows).
Sorry for my english, hope you got the point :hmm:
Joel Hooks
07-09-2003, 03:05 PM
Now that's an interesting trick. I would have never even thought, you can light all your features individually that way. I guess you'd have to be careful about angles and such, but it would even work could if you divided the scene into a grid for coverage. Thanks to both of you for the thoughts!
Has anybody else come up with a solution for this problem?
Dave Black
07-09-2003, 03:05 PM
You can also experiment with using the "overshoot" function. Basically makes a spot illuminate like both an omni and a spot. You can use it to focus your shadows.
Aside from that, though, have you tried using area shadows? Works really well in outdoor scenes.
-3DZ
:D
Joel Hooks
07-09-2003, 03:14 PM
I can't have the overhead. I want nice tight shadows on my features, but keep my render times low. I've used overshoot and such, but my scenes are viewed top-down, birds-eye, and eye height so it needs to look good (as well as consistant) across the entire scene while maintaining speed.
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